Adjustable hitch mechanism for tractor-mounted plows



June 25, 1957 H. E. ALTGELT 2,796,817

ADJUSTABLE HITCH MECHANISM FOR TRACTOR-MOUNTED PLOWS Original Filed Sept. 2. 1950 3 Sheets-Sheet 1 v INVENTOR.

HERMAN E. ALTGELT h A ORNEYS June 25, 1957 H. E. ALTGELT 2, ,8

ADJUSTABLE HITCH MECHANISM FOR TRACTOR-MOUNTED FLOWS Original Filed Sept, 2. 1950 3 Shets-Sheet 2 FIG. '2 156 4 ll 8 I; 74 F a? a I66 IO 46 ,t I67 2 vi 3 56 54 FIG. :0 53 f .67 L 4 57 I66 INVENTOR.

HERMAN E. ALTG/ELT June 25, 1957 H. E. ALTGELT ADJUSTABLE HITCH MECHANISM FOR TRACTOR-MOUNTED FLOWS Original Filed Sept. 2. 1950 3 Sheets-Sheet 3 IN V EN TOR. HERMAN E. ALTGELT AiORNEYS Stes ADEUSTABLE HITCH MEfIHANISM FOR TRACTGR-MQUNTED PLGWF) Herman E. Altgelt, Moline, 111., assignor to Deere & Company, Mo'iine, BL, a corporation of l'iiinois 12 Claims. (Cl. 9747.52)

The present invention relates generally to agricultural implements and more particularly to implements that are adapted to be mounted on a tractor and raised, lowered and controlled by means on or driven by the tractor.

The object and general nature of the present invention is the provision of a tractor-mounted implement and means operated by the rockshaft of the tractor power lift unit for both adjusting the depth of operation of the implement and raising the latter into its transport position. More particularly, it is a feature of this invention to provide lifting and controlling connections arranged with lost-motion means whereby the implement remains substantially unaffected by variations in the position of the tractor relative to the implement, as when the rear wheels of the tractor run over a ridge or the front wheels pass into a depression or the like. Further, it is an important feature of this invention to provide means incorporated in the connections between the implement and the tractor facilitating the leveling of the implement relative to the tractor.

An additional feature of this invention is the provision of an agricultural implement of the type in which groundworking tool means is connected with the tractor through vertically swingable, generally parallel link means, affording a virtual hitch point well forward of the points of actual connection of the implement with the tractor, in connection with means providing a lost-motion connection in the upper link, whereby the latter is enabled to transmit all compressive forces encountered in normal operation but which does not abruptly raise the rear end of the implement if perchance the front wheels of the tractor should drop into a ditch, depression or the like or the rear wheels of the tractor pass over a ridge or hump while the outfit is in operation.

These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a perspective view of a tractor-mounted disk plow in which the principles of the present invention have been incorporated.

Figure 2 is a plan view of the disk plow shown in Figure 1.

Figure 3 is a diagrammatic view showing the action of an implement, constructed according to the principles of the present invention, maintaining substantially the desired depth of operation even though the front wheels should, for example, pass into a depression, such as a dead furrow or the like.

Figure 4 is a sectional view, taken along the line 4-4 of Figure 2, showing the mechanism for leveling the plow laterally.

Figure 5 is an enlarged fragmentary sectional view taken along the line 5-5 of Figure 4.

Figure 6 is a perspective view of the crank screw actuated adjustable abutment forming a part of the lateral leveling mechanism shown in Figure 4.

Figure 7 is a perspective view showing the principles tent O Patented June 25,. 1957 of the present invention embodied in a two-bottom moldboard tractor carried plow in which the entire plow is lifted and carried entirely on the tractor during transport.

Figure 8 is an enlarged fragmentary perspective showing the rear end of the compression or upper link in this form of the invention.

Figure 9 is a diagrammatic View, somewhat similar to Figure 3, showing the implement in this form of the invention in its raised or transport position.

Figure 10 is a detail view of a novel tractor drawbar construction.

Referring now to the drawings, the implement, which is indicated by the reference numeral 1, is shown as connected to a farm tractor 2, which is of conventional construction so far as the present invention is concerned. The tractor 2 includes front wheel means and rear wheel ice . means 3 driven by a power plant 4 of any suitable construction, which also energizes a power-actuated mechanism 5 of the type generally referred to as a power lift. The mechanism 5 includes a transversely disposed rockshaft 7 carrying power lift arms 8 fixedly connected at the ends of the rockshaft 7, the outer ends of the power lift arms 8 being connected by lost-motion or normally slack link means 9 with the drawbar 10 of the tractor. The drawbar 10 of the tractor is connected for generally vertical swinging movement about a transverse axis relative to the tractor, and the power lift unit 5 is constructed substantially the same as that shown in U. S. Patent 2,477,710, issued August 2, 1949 to Charles C. Worstell, to which reference may be made if necessary. By means disclosed and claimed in the patent just mentioned, the power lift rockshaft 7 may be rocked progressively in controlled increments in the raising direction by operat ing a control arm 11 in the desired amount and direction, the rockshaft 7 then moving a corresponding amount in that direction.

According to the principles of the present invention I provide a tractor-carried implement 1 so constructed and arranged that the operating depth of the implement may be adjusted or varied by movement of the rockshaft 7 through a range of movement which corresponds to the slack position of the lifting links 9, movement of the rockshaft 7 beyond that position acting through the drawbar 10 to raise at least the front end of the implement toward its transport position. The means provided for this purpose will be referred to later in detail.

The implement 1 is constructed in the form of a disk plow having a generally diagonally extending beam structure 15 to which the upper portions of a pair of diskstandards 16 are adjustably connected. The lower portion of each standard 16 carries suitable bearing units 17 by which rotatable furrow opening disks 18 are operatively connected with the standards 16. The upper ends of the standards 16 are bent forwardly and secured, as by bolts 19, to the beam structure 15. A rear frame extension 21 is secured to and forms a part of the beam structure 15 and at its rear end carries a generally vertically extending sleeve 22 in which the spindle portion 23 of a rear furrow wheel axle 24 is disposed for movement about a generally vertical axis. An arm 25 is fixed to the upper end of the spindle 23 and the lower end of the axle structure 24 carries a relatively heavy rear furrow wheel 27. The outer end of the arm 25 is apertured to receive the rear end of a link 28 which at its forward end is threaded and extended through an apertured bracket 29 secured to the plow frame 15. A threaded end of' the link 28 carries lock nuts 31 by which the position of the arm 25 may be varied and adjusted, as desired, to vary or adjust the angle of lead of the rear furrow wheel 27.

A vertical frame section 35 is fixed to and forms a part of the plow frame structure 15, the section 35 including a pair of downwardly converging bars 36 welded at their rear edges to a strut section 37, The lower ends of the two bars 36 are apertured to receive a transverse hitch pin 38, the lower portion of the strut 37, below themain portion of the frame 15, being reenforced by a gussetplate 39. The upper ends of the downwardly converging bars 36 are apertured to receive a transversetpin or bolt 42 which is-heldin placebya cotter orthe like. A ver-- tically disposed frame part 46 is connected to and forms. a part of the frame structure 15 through the pivot bolt 38 mentioned above. The frame part- 46- includes a lower, transversely disposed, generally u shaped socket' member 47' and an upwardly extending plateisection 48 which is disposed in a vertical fore and: aft extending. plane and welded at its lower end to the socket member 47; The lower end'of the vertical plate 48-is aperture'd to receive the hitch pin 38. The vertical: plate-'48':i'sreenforcedby a-pair of lateral gussets 49,

The U-shaped socket memberv 47 include's'vertically spaced'sections- 51 and 52 which are spaced apart, so; as to receive therebetween a transverse drawbar member 53,. which, according to the principlesof the present invena tion, is provided with a plurality'of apertures 54c and is pivotally connected at its ends to rear portions"v of the sidearms 56 and 57 of the tractor drawbar 10. A hitch pin 59 is extended through apertures in the upper and. lower members 51' and 52 of the socket member'47 and through a selected aperture in the drawbar'member 53, the parts being arranged so that when the socket memher 47 is connected through the pin 59 with. the bar. 53,: there is some clearance betweenthe rear edge' oftheibar: 53 and the adjacent or bight portion of the U-shaped. socket member 47, as will be seen from Figure l, whereby the implement 1' may swing laterally relative to the tractor, particularly the drawbar 10 thereof. Details of the noveltractor drawbar 10 will be described later.

As best shown in Figure 1, a depth-adjusting. or controlling. arm 62 is fixed to the generally central portion of the rockshaft 7 and extends generally downwardly and rearwardly with respect to the power lift arms 8'. The lower end of the depth-adjusting arm 62 is apertured to receive the forward end of a compression link structure 63; the latter being pivotally connected by any suitable pivot pin or the like to the outer end of the controlling arm 62; The rear end of the compression link 63 is slotted, as at 64, theslots 64 thereof receiving a pivot pin 66 which connects the rear endof the compression link 63' to the upper end of the forward frame part' 46'.- The vertical plate portion 43; of the front frame part 46'- is apertured below the pin 66, asat 67 (Figures 4;a'nd to receive the transverse'pin 42. The transverse pin 42 and the portions of the vertical plate 48 receiving it serve to-pre'vent any pivoting in a vertical plane of one frame part relative to the other about the axis ofthe lower hitch pin 38; but the part associated with the hitch pin 38 provide sufiicient looseness so that therear frame part, carrying the disks 18, may be pivoted or tiltedlaterally relative to the front frame part 46 abouta generally fore and aft extending axis.

Means is provided for adjusting the laterally tiltedp'osition of one frame part relative to the other, and: such means comprises a crank screw 71 extending through apertures ,in the downwardly converging frame bars" 36' and held in place therein by a pair of collars 72. The threaded portion 81 of the crank screw 71 receives a nut member 74 that is rockably mounted in the upper-- por tion of a keyhole type aperture 75 formed in the upper portion-of the front frame plate 43. The nut member is formed with a pair of opposed abutments 76 at each side shaped to=accornmodate relative rocking movement of the nut member 74' with respect to the plate member: 75 about an axis-which passes generally centrally through the threaded portion of the crank screw 71. The not member 74is mounted in place in the front frameplate section 48 by first inserting the. nut member 74.in:the

lie on opposite sides but substantially in the horizontal plane of the axis of the threaded portion of the crank screw 71; Therefore, there is little. if any. tendency for side. thrusts transmitted between the frame parts causing the nut member 74 to bind on the threaded portion of the crank screw 71.

The operation of the implement described above is substantially as follows.

Figure 1 shows the implementlini operating position, in

which it will be noted that the furrow: openers 18 'lie well' below the transverse pivot axis of the connection 38 betweenthe front endof the. frame structure 15-and the rear portion of the tractor drawbar'10.- Normally, therefore, the pressure of the soil, or thesoil resistance, tends to cause the implement frame to rock upwardly and forwardly about the aforesaid axis. This, however, is resisted by the link 63 acting'in. compression, the normal position of the parts being that in which the pivot 66 presses forwardly against the forward end of the slot 64,. the forward end of the link 63 being pivoted to the depth-adjusting arm 62. Since the drawbar 10, whichserves as a lower link, and the compressionlinks 63, which serves as. an upper link, are free topivot upwardly, and also downwardly within the limits of the slack in the chains. or links 9,.the implement as a whole swings generally vertically about a virtual hitch point which lies well forward ofthe tractor, generally at the point ofconvergence of the upper and lower links63 and 10.- If, however, the frontv end of the tractor should drop into a depression, such as a dead furrow or the like, or the rear wheels of. the tractor pass-over a ridge or hump,

which ordinarily would cause the links- 9 to tighten and hence act through the drawbar 10 to abruptly lift the rear end of the implement from the ground, the pin 66' moves rearwardly in the slot 64, which thus'permits thei-rear end of the implement to remain on the ground while the wheels of the tractor pass over the depressions andlridgesr In: this way, the tractor 2 may oscillate generally vertically, either at its-frontor rear end, without materially affecting the position of the plow. Since in normal operation; the pin 66 lies at the' forward end of the slot 64, the presence of the latter, which allows thetractor to tilt as aforesaidwithoutchangin'g the position v of. the plow, is of no disadvantage, for normally the soil resistance causes the pin 66 to' lie at the front end of the' slot- 64. Moving the'rockshaft 7 into different positions during" normal operation acts: through the upper or compression link- 63 to change the position-of' the implement, causing it to operate at-an increased or decreased depth, according. to whether the rockshaft 7 is operated in a direction to move the end of the adjusting arm 62'- downwardly and forwardly, or upwardly and rearwardly. The lifting chains 9 are normally slack during operation; the depth of operation being determined by the position of the rear furrow wheel 27 and-the position, in a generally fore-and aft direction, of the lower end of the arm 62 and the forward end of the link 63, variations of which, as by rockingtof the sh'af t-7j act to sh'ift the-virtual hitch point, which lies atthe intersection of thelines of the links 63, 56 and 57 extended, of the implement.

In the'implement described above, the furrow openers are disks and, as is well known, disk plows and similar machines-usually require a fairly heavy rear furrow wheel in order togive the implement suflicient penetration to enter the ground promptly when beginning a f-urrow. In

suchaimplements it is not desirable to" raise: the rear end of the implement off the ground when lifting the implement into its transport position. However, it is ordinarily entirely feasible to lift other types of implements entirely clear of the ground with the ordinary power lift means of the tractor, because there is no necessity of having the rear end of such implement heavily weighted as in disk plows and the like.

Referring now to Figures 7 et seq., the implement shown may readily be entirely lifted off the ground for transport purposes and the like by the power lift of the tractor, and in illustrating this form of the invention I have shown a two-bottom plow 101 connected to the same tractor described above in connection with the disk plow shown in Figures 1-6. Parts that are identical with those described above will be indicated by the same reference numerals.

The two-bottom plow 101 comprises a plow frame structure 102 which includes a right-hand beam 103, a lefthand beam 104 and suitable diagonal braces 105 and 106. Plow bottoms 107 are fixed to the lower ends of standards 103 which are rigidly connected to the rear ends of the plow beams 103 and 104 by connecting brackets 109, which are largely conventional, so far as the present invention is concerned. A rear furrow wheel 111 is mounted at the lower and rear end of a supporting crank axle 112, the position of which relative to the frame of the plow may be varied, as desired, by an adjusting link 113.

The plow frame 102 includes at its forward end an upwardly extending frame structure 115 which includes a plate section 116 bent so as to form a rearward brace section 117 bolted to the brace member 105 at 118, by bolts or the like, and a transverse vertically extending plate section 119 which is reenforced by a second bracing section 121 which is welded at its forward end to the transverse plate section 119 and fastened to the plow beam 103 by any suitable means, such as bolts 122. Secured, as by welding, to the forward side of the vertically extending transverse plate section 119 is a pair of upwardly diverging vertical bars 125 and 126 which are apertured to receive an upper connecting pin 127 which is substantially the same as the corresponding part 42 described above. Below the pin 127 the bars 125 are apertured to receive a crank screw 128 which is also substantially the same as described above and held in place against lateral displacement relative to the bars 125 and 126 by the same collar and pin means. The lower ends of the bars 125 and 126 are apertured to receive a hitch pin 131 by which the vertically extending structure 115 is connected to a vertical frame section 135 which preferably is substantially the same as the vertical frame structure 46 described above, and which is connected with the tractor by the same socket member and link structure described in detail above, and hence further description here is unnecessary.

The operation of the plow just described is substantially the same as that of the disk plow described above, except that when the power lift unit is operated to raise the implement into its transport position, the front end of the plow frame 102 is raised first, until the attaching pin 66 reaches the rear end of the slot 64, after which further raising movement transmitted to the tractor drawbar raises both the front and rear ends of the implement so that the latter entirely clears the ground. as shown in Figure 9.

The present invention, as embodied in either of the plows described above, is particularly adapted for use with a tractor having the drawbar construction indicated in its entirety by the reference numeral 10 and referred to briefly above. As will be seen particularly in Figure 10, the tractor drawbar 10 has the side arms 56 and 57 interconnected rigidly by a solid cross member 161, the ends of which are rigidly fixed, as by welding, to the side arms 56 and 57 at points a short distance ahead of the pivoted hitch member 53. Since the side arms 56 and.57 arerigidly tied together, the drawbar 10 as a whole is a rigid part or member. The forward ends of the side arms 56 and 57 are apertured to receive pivot studs 162 by which the drawbar 10 is connected with the tractor for vertical swinging movement relative thereto about the transverse axis defined by the studs 162. This provides a drawbar construction'with which implements may easily and conveniently be connected so asto be held by the drawbar against lateral tilting,'or lateral swinging movement under transversely directed forces. The present construction, therefore, makes it unnecessary to interconnect the implement with some other part of the tractor, such as the transverse power lift shaft, thereby relieving the power lift shaft of such loads. At the same time, the extension of the side arms of the drawbar rearwardly of the rigid interconnecting bar 161 and the arrangement and' construction in which the transverse hitch member 53 is pivoted, as at 164, to the rear ends of the side arms 56 and 57, makes it very easy and simple to connect the hitch structure of various implements to the tractor through the tractor drawbar 10 and, by virtue of the pivoting of the hitch member 53 in the drawbar side arms, up-and-down swinging of the implement relative to the tractor is readily accommodated. The forward ends of the tractor drawbar side arms 56 and 57 are shown as pivoted, as at 162, to rearwardly extending lugs 166 on the sides 167 of the differential housing, but it will be understood that a tractor drawbar, such as the one described above and indicated by the reference numeral 10, may, if desired, be pivotally connected with some other part or portions of the tractor.

While the implement shown in Figures 1-6 has been described as supported on the rear furrow wheel 27 for transport, it will be understood that by properly proportioning the slot 64 and the range of operation of the lifting mechanism, the implement 1 may be raised entirely off the ground for transport, in much the same manner as the plow 101, provided the rear wheel 27 is not too heavy.

In both forms of the invention described above, the plow is free to swing laterally relative to'the tractor, not only by virtue of the pivoting of the hitch member 46 to the hitch bar 53 by the pivot 59, but also by virtue of the connection of the plow frame through the hitch pin 38. to the vertical section 48 of the front hitch structure, this connection afiording some looseness which, together with a certain amount of looseness between the pin 42 and nut member 74 relative to the plate 48, provides an amount of lateral swinging of the implement relative to the tractor in addition to that provided by the permissive swinging of the hitch structure 46 relative to the tractor drawbar 53. Thus, a plow or other implement incorporating the principles of the present invention is especially adapted for contour work and other operations where relatively unhampered maneuverability is desirable.

While I have shown and described above the preferred structure in which the principles of the present invention have been incorporated, it will be understood that my invention may be embodied in types of implements other than described specifically above. For example, the disk plow is representative of any implement in which there is a rear support which is in contact with the ground, both in the operating and in the transport positions, whereas the second form of the invention described above is representative of any implement in which the entire implement is raised relative to and carried entirely by the tractor during transport. For example, instead of a plow having two moldboard-type furrow openers, only one furrow opener may be employed, or the ground-engaging means may be in the form of a disk harrow, either the offset type or the singleor double-action type, as desired.

Therefore, what I claim and desire to secure by Letters Patent is:

1. An agricultural implement adapted to be attached to a" tractor of the type' having a drawb ar' including a transversely extending section, said implement comprising a frame having twoparts interconnected for relativemovement about a generally fore and aft extending axis,

one of said frame parts having a lower drawbar-receiving' lateral tilting relative to the tractor, ground engaging means connected totheother frame part; said'one frame part being swingable generally vertically relative to the tractor and saidother part having a' forwardly disposedsection extending upwardly alongside said above-men tioned second section, means acting" between thelatter section'and said forwardly disposed section for changing the'position-of one frame part relative to the-other about said fore and aft extending axis" soas to provide for levelingthe implement by changing its position relative to the tractor, and a compression member connected at its rear end with the upper end of said second section and-adaptedto be connected at its forward endwith'the tractorabove the drawbar.

2. For'use with-a tractor of the typehaving a generally vertically swingable drawbar and power actuated means for swinging said drawbar, including a rockshaft, means for controllably rocking the latter through successive increments, and armmeans fixed to said rockshaft and having a lost-motion connection with said drawbar, the

combination-with an arm adaptedto be fixed to said rockshaftat anintermediate point of an implement comprising frame means including a generally rearwardly extending' part and an' upwardly extending part, means for pivotally connecting the forward end of said rearwardly extending frame part to said drawbar for generally vertical movement relative thereto about a transverse axis,.

movement about a fore and aft extending axis, and means for tilting one frame part laterally about said fore and aft extending axis relative to the other frame part.

4. The invention set forth in claim 3, further characterized by said compressionlink including lostmotion means whereby after said power actuated means has been actuated to take up the lost motion means-in the connection between said arm means and said drawbar, further operation of said'power actuated-means serves to raise only the front end of said frame-until the lostmotion in said com-' pression link has been taken up, after which further operation of the power actuated means serves to raise both ends of the implement-means relative to the tractor.

5. An agricultural implement adapted to be connected with a tractor of the type having a generally vertically swingable drawbanrpower actuated means for swinging said drawbar, including arockshaft, means for controllably rocking the latter through successive increments, arm means fixed to said rockshaft and having a lostmotion connection with said drawbar, anda depth adjusting arm fixed to said rockshaft at an intermediate'point, said implement comprising frame means including a generally rearwardly extending part and an upwardly extending part, means for-pivotally connectingthe forward end of said rearwardly extending frame'part to said drawbar for generally vertical movement'relative thereto about a transverse axis, and a compression link meanspivotally connecting the upper end of said upwardly extending frame partwith said last mentioned-arm and adapted to swing said implement frame relative to said drawbar about said transverse axis by rocking'movement of said rockshaft before the lost motion inusaid lost motion: connec tion has be'en' taken up'by upward-movement of said' arm 63 plow'adapt'ed tobe' connected with a tractor of the'type'having a generally vertically swingable drawbar,

power actuated means for swinging said drawbar including a rockshaft, means for controllably rocking the latter through successive increments; arm means fixed= to said roclishaftand having a lost-motion connection-with said drawbar, and a'dep'th adjusting armfixed to said rockshaft at an intermediate point, said plow comprising frame means including a generally rearwardly extending part andan' upwardly'ext'ending part, meansfor pivotally connecting theforward" end of saidrearwardly extending framepart to said drawbar for generally vertical movement relative thereto about a transverse axis, and a compression link means pivotallyconnecting the upper end of said upwardly extending frame part with said last mentioned' arm and adapted to swing said implement frame relative to said drawbar'about said transverse axis by rocking movement of said rockshaft' before the lostmotion in-saidlostmotion connection has been" taken up by up ward movement of said arm means;

7'. A hitcli' device comprising a generally transversely disp'oseds'ocket-member'having a drawhar-receiving socket and'a generally vertically extending plate section arranged tolie 'ina generally fore-and-aft' extending vertical plane, frame means connected at its forward lower portion with said socket member and having a forward generally-verticallyextending section disposed alongside said first sectionand including a pair oflat'erally spaced apart bars disposed generally vertically and on opposite sides ofsaid plate section, andiadjusting member carried by said bars, and means connected with said plate section and said adjusting member andoperated'by movement of the latter to sliift saidframe means relative to-said socket member.

8. A'- hitchdevice comprising agenerally transversely disposed socket m'ember having adrawbar-receivingsocket and agenerally vertically extending section fixed at its lower portion to-saidsocket member, frame means connected at its for wa'rd lower'portion withsaid' socket memher and having a forwardgenerally vertically extending section disp'osed' alongside said first section, said-last mentioned vertically extending section including spaced apart members disposedgenerallyon opposite sides of said first mentioned vertical section, the latter being apertured, a transverse part extending through the aperture insaid apertured" se'ction' and connected-at its ends to said-spaced apartmemberspand an adjustingmember carried by one section and-connected with the other section for changing the position of saidframe means relative'to said socket member.

9. A- hitch device comprising a generally transversely disposedso'cket member having adrawbar-receiving socket and a generally vertically extending plate section arranged to lie in a generally fore-and-aftextending vertical plane, said plate section having a-pairof apertures in its'upper portion, frame means connected at its forward lower portion with the lowerend of said plate section for lateral pivoting and having a forward generally vertically extending secti'ondisposed alongsidesaidfirst section, the latter section includinga pair of laterally spaced'apart bars disposed generally vertically and on opposite'sides of said plate section; a transverse part extending'through one of the apertures in said plate section and fixed at its endportions to said laterally spaced apart bars, a nut member carried in the other'of said apertures, and a screw threaded adjusting member extending'through said not member and turnably'connected at its end portions with said laterally spaced apart bars.

10. For use-with a tractor of the type having a generally vertically; swingable drawbarand power actuated cessive: increments, and" armv means: fixed to said rockshaft and having a lost-motion connection with said drawbar, the combination with an arm adapted to be fixed to said rockshaft, of an implement comprising frame means including a generally rearwardly extending part and an upwardly extending part, means for pivotally connecting the forward end of said rearwardly extending frame part to said drawbar for generally vertical move ment relative thereto about a transverse axis, and a compression link means pivotally connecting the upper end of said upwardly extending frame part with said last mentioned arm and adapted to swing said implement frame relative to said drawbar about said transverse axis by rocking movement of said rockshaft before the lost motion in said lost-motion connection has been taken up by upward movement of said arm means.

11. For use with a tractor of the type having a generally vertically swingable drawbar and power actuated means for swinging said drawbar, an agricultural implement comprising frame means and means for connecting said frame means with said drawbar for movement relative thereto about a generally transverse axis, an upper link member adapted to be pivotally connected at its upper end with the tractor at a point above said drawbar, and means including a pin and elongated slot type of connection between the rear end of said upper link means and the implement at a point above said axis, said pin and slot connection comprising a slot in the rear portion of said upper link and extending generally longitudinally thereof, a pin freely movable in a generally fore-and-aft direction in said slot, and means connecting said pin with the implement, the distance between the forward end of said slot and a point of pivotal connection of the upper link with the tractor being such that when the tractor is generally horizontal in operation, said implement is also generally horizontal, said slot accommodating a free rearward movement of the pin when the tractor tilts forwardly relative to the implement.

12. For use with a tractor of the type having a generally vertically swingable drawbar and power actuated means for swinging said drawbar, an agricultural implement comprising frame means and means for connecting said frame means with said drawbar for movement relative thereto about a generally transverse axis, an upper link member adapted to be pivotally connected at its upper end with the tractor at a point above said drawbar, and means connecting the rear portion of said upper link member with the implement at a point generally above said axis, said last mentioned connecting means including a part connected with the implement and having a lost-motion connection with said upper link member and means spaced apart longitudinally of said upper link member to limit the amount of relative movement between said part and said upper link member, the distance between said spaced apart means being such that when the tractor is generally horizontal in operation and said upper link member is under compression said implement is also generally horizontal, said spacing accommodating a free rearward movement of said part relative to said upper link member when said drawbar is raised, said spacing being sufficient to accommodate an upward tilting of the implement until the rearward relative movement of said part is terminated, said part being movable freely relative to said link member during the range of said lost motion.

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